The present invention relates generally to winches and, more particularly, to an improved method for using and mounting a winch.
Motor vehicles traveling on non-hardened surfaces often get bogged down, particularly in mud, snow, sand or rock-filled terrain. To allow the driver of the vehicle to extricate the vehicle and to continue travel without outside assistance, motor vehicles designed for travel on non-hardened surfaces are often equipped with a winch, most often attached to the front of the vehicle. When needed, the cable of the winch is attached to a fixed object such as a tree or a large stone and the winch is activated to pull the vehicle out of the terrain in which it is bogged down.
Due to the availability of electricity in motor vehicles and the technical case with which it can be utilized, electrical-power motorized winches are often used. Mechanical-power winches directly coupled to the vehicle motor (power take-off) or equipped with a dedicated internal combustion motor or hydraulic-power winches with power supplied by the power-steering pump of the vehicle are also common.
As illustrated in FIG. 1, winch 10 is typically mounted on vehicle 12 so that drum rotation axis 14 is parallel to an underlying surface 16 on which vehicle 12 rests and perpendicular to the main vehicle axis 18. Often a slot-shaped cable guide 20, known as a fairlead, is attached in front of winch 10 to guide cable 22.
Due to engineering constraints, the maximum number of wraps of cable on a winch drum is limited so that the full length of cable can be wound onto the drum only if each wrap is tightly wound and complete. When the winch cable is attached to an object substantially directly in front or behind the vehicle and the winch is activated, the drum rotates, winding the cable and pulling the vehicle. In FIG. 2a, cable 24 being wound is initially positioned next to or just above an immediately previously wound length of cable 26 on a winch drum 28. Due to the thickness and the substantially round cross section of cable 24, cable 24 slips downwards (FIG. 2b) and in this manner is wound onto drum 28 tightly against the immediately previously wound length of cable 26. When cable 24 reaches one end of the drum, a wrap is complete. The following length of cable 30 cannot slip downwards, so a new wrap is initiated (FIG. 2c). Thus, when the winch cable is attached to an obstacle substantially directly in front or behind the vehicle, the cable is tightly wound onto the drum.
It can happen that the winch cable is attached to an object so that the winch cable emerges from the fairlead at a significant sidewards angle, either initially or due to slipping of the vehicle during the pulling activity. Here, xe2x80x9csignificant sidewards anglexe2x80x9d means from about 2xc2x0 left or rightwards. Since a winch is typically mounted perpendicularly to the main axis of the vehicle it can be said that the cable is connected to an object that is off-axis relative to the vehicle, that is, it is not found along the axis of the vehicle.
If this angle is in the direction away from the immediately previously wound length of cable, FIG. 3a, new lengths of cable 32 are wound with spaces 34 between the wound lengths of cable 32. If the angle is in the direction towards the immediately previously wound length of cable, FIG. 3b, newly wound lengths of cable 36 climb onto the previously wound length of cable 38 despite not having completed a wrap.
Improper winding is undesirable. Since the wraps are incomplete and not tightly wound, the full length of cable cannot be utilized to extricate the vehicle. Furthermore, it is well known to one skilled in the art that if the cable climbs onto a previously wound lengths of cable the torque, and thus the power exerted by the winch through the cable, is reduced. It is thus preferable to wind wraps tightly to maintain the maximal torque for as long as possible.
Improper winding is also dangerous. While it is being improperly wound, the cable can extend outside its designed volume and cause serious damage to the winch housing or parts of the vehicle such as the fender. If the cable climbs onto an incomplete or not tightly-wound wrap, the force applied by the newly wound cable on the wrap may force the cable down into the spaces of the wrap. This damages the cable, leading to internal fraying or caging. Once damaged, it is dangerous to use the cable as it may knick or tear. Furthermore, since the price of a cable can reach 15% of the price of a winch, frequent cable replacement is economically undesirable.
In order to avoid cable damage, extrication of one vehicle often requires the assistance of an additional vehicle.
It would be advantageous to be able to use a winch when the cable is attached to an object so that the cable extends at a significantly sidewards angle and yet avoids the difficulties described hereinabove.
The above and other objectives are achieved by the innovative method of using a winch and by using the innovative winch mount provided by the present invention.
The use of the teachings of the present invention allows greater extrication ability by removing the force-absorbing fairlead and allowing use of the powerful first wrap of the winch for a longer distance. The use of the teachings of the present invention allows safe winch operation by avoiding cable and vehicular damage. The use of the teachings of the present invention increases the self-extrication ability of a vehicle. By reducing the strain during operation, the lifetime of the winch motor can be prolonged.
According to the teachings of the present invention there is provided a method of operating a winch attached to a first object, the winch being employed to draw the first object and a remote second object together when the second object is off-axis from the first object by more than 2xc2x0. The method includes the steps of a) attaching the cable to the second object; b) activating the winch; and c) moving the winch relative to the first object so as to align the winch, so that when the winch is activated, the force exerted by the cable on the winch drum is substantially perpendicular to the drum rotation axis.
According to a further feature of the present invention, the first object on which the winch is attached is vehicle or a nautical vessel.
According to a further feature of the present invention, alignment of the winch includes rotating the winch around an alignment axis, the alignment axis being substantially perpendicular to the drum rotation axis. According to a still further feature of the present invention, the first object on which the winch is attached is a vehicle and the alignment axis is substantially parallel or substantially perpendicular to the surface on which the vehicle stands.
According to a further feature of the present invention, alignment of the winch is performed with the help of a motor.
According to a further feature of the present invention, alignment of the winch is done preceding and/or during operation of the winch in order to maintain the perpendicularity of the force relative to the drum rotation axis throughout operation of the winch.
According to a still further feature of the present invention, a device is provided to determine the direction of the force or to determine the angle of the cable relative to the drum rotation axis.
There is also provided according to the teachings of the present invention a winch mount made up of a mount-base and a winch-holder. The mount-base is attached to some object such as a vehicle. The winch holder is configured to hold the winch in a fixed position, and is rotatably mounted along an alignment axis, the alignment axis being substantially perpendicular to the winch drum rotation axis.
According to a further feature of the present invention, there is provided a alignment mechanism for rotating the winch-holder around the alignment axis, such as a motor, in particular, an electric or a hydraulic motor.
According to a further feature of the present invention, there is provided a winch control unit to simultaneously monitor and regulate activation of the winch and of the alignment mechanism. According to a still further feature of the present invention the winch control unit control includes a computer.
According to a further feature of the present invention, there is provided a remote control mechanism to control the mechanism of rotation, the remote control mechanism including a cable or an infrared or radio frequency transmitter which sends the commands of the operator to a winch control unit.
According to a further feature of the present invention there is provided a device for determining the angle of the force exerted by the cable relative to the winch drum or to determine the angle of the cable relative to the winch drum rotation axis. Further there is provided a mechanism to automatically control the motor to rotate the winch-holder around the alignment axis in accordance with the angle determined by the device.
According to a still further feature of the present invention the device for determining the angle of the force exerted by the cable relative to the winch drum or to determine the angle of the cable relative to the winch drum rotation axis includes a radiation detector, such as a light sensor, or a sensor that measures pressure such as one using a piezoelectric material.
According to a still further feature of the present invention, there is a sensor that determines a magnitude of a force applied parallel to the drum rotation axis.